Slow-Roasted Balsamic & Thyme Onion Jam

🌍 Cuisine: French-American Fusion
🏷️ Category: Condiments & Sauces
⏱️ Prep: 15 minutes
🍳 Cook: 60-75 minutes
👥 Serves: 2 cups

📝 About This Recipe

This luxurious condiment transforms humble yellow onions into a deep, mahogany-hued relish that balances savory, sweet, and tangy notes. By slowly caramelizing the onions in butter and olive oil before deglazing with aged balsamic vinegar, we unlock a complex depth of flavor that mimics fine charcuterie accompaniments. It is the ultimate secret weapon for elevating burgers, cheese boards, or simple crusty bread into a gourmet experience.

🥗 Ingredients

The Aromatics

  • 3 pounds Yellow Onions (peeled, halved, and thinly sliced into half-moons)
  • 3 pieces Garlic Cloves (minced very finely)
  • 4 sprigs Fresh Thyme (leaves removed and stems discarded)

The Cooking Base

  • 2 tablespoons Unsalted Butter (high quality)
  • 2 tablespoons Extra Virgin Olive Oil
  • 1 teaspoon Kosher Salt (plus more to taste)
  • 1/2 teaspoon Black Pepper (freshly cracked)

The Sweet & Tangy Glaze

  • 1/4 cup Granulated Sugar
  • 2 tablespoons Brown Sugar (packed)
  • 1/2 cup Balsamic Vinegar (use a decent quality, slightly syrupy brand)
  • 1/4 cup Red Wine Vinegar (for a bright acidic punch)
  • 1/4 cup Water (to help dissolve sugars if needed)

👨‍🍳 Instructions

  1. 1

    Prepare your onions by cutting off the ends, peeling back the skins, and slicing them into uniform 1/8-inch thick half-moons. Consistency is key for even caramelization.

  2. 2

    In a large, heavy-bottomed Dutch oven or deep skillet, melt the butter and olive oil over medium heat until the butter begins to foam.

  3. 3

    Add the sliced onions to the pot and toss thoroughly to coat every strand in the fat. Sprinkle with the kosher salt to help draw out moisture.

  4. 4

    Cook the onions over medium heat, stirring every 5 minutes, for about 20-25 minutes. They should soften significantly and reduce in volume by half.

  5. 5

    Reduce the heat to medium-low. This is the patience phase. Continue cooking for another 20 minutes, stirring more frequently to prevent sticking, until the onions are a golden straw color.

  6. 6

    Add the minced garlic and fresh thyme leaves. Sauté for 2-3 minutes until the garlic is fragrant but not browned.

  7. 7

    Sprinkle both the granulated and brown sugars over the onions. Stir well and cook for 5 minutes; the sugar will melt and begin to create a glossy sheen.

  8. 8

    Pour in the balsamic vinegar, red wine vinegar, and water. Use a wooden spoon to scrape up any brown bits (fond) from the bottom of the pan—that is pure flavor!

  9. 9

    Simmer the mixture over low heat for 15-20 minutes. The liquid should reduce and thicken until it reaches a jam-like, syrupy consistency that coats the back of a spoon.

  10. 10

    Stir in the freshly cracked black pepper. Taste the jam—it should be a harmonious balance of sweet, salty, and acidic. Adjust with a pinch more salt if necessary.

  11. 11

    Remove from heat and let the jam cool completely in the pan. It will continue to thicken as it reaches room temperature.

  12. 12

    Transfer the cooled jam to sterilized glass jars. Store in the refrigerator for up to 2 weeks.

💡 Chef's Tips

For the best flavor, use a mix of yellow and red onions to add color and complexity. Never rush the caramelization process; high heat will burn the natural sugars and make the jam bitter. If the jam becomes too thick after cooling, stir in a teaspoon of warm water or a splash of vinegar to loosen it. If you prefer a spicy kick, add a pinch of red pepper flakes during the sugar-adding stage. Always use fresh thyme; dried thyme can be too woody for the delicate texture of this jam.

🍽️ Serving Suggestions

Spread a thick layer onto a toasted baguette topped with creamy Brie or goat cheese. Use it as a premium topping for a Wagyu beef burger with arugula and blue cheese. Whisk a tablespoon into a homemade gravy or red wine reduction for roasted meats. Pair with a sharp aged Cheddar and a glass of bold Cabernet Sauvignon or a smoky Stout. Fold into a grilled cheese sandwich made with sourdough and Gruyère.